Detection of Audio Capture

Technique Detected:  Audio Capture | T1429

ID: DET0673
Domains: Mobile
Analytics: AN1772, AN1773
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN1772

A defender observes an application holding microphone capture capability transitioning into active microphone resource usage through Android audio APIs (e.g., MediaRecorder or AudioRecord), followed by sustained capture while the application is backgrounded or the device is locked, and subsequent outbound network traffic suggesting potential audio exfiltration or streaming.

Log Sources
Data Component Name Channel
OS API Execution (DC0021) android:logcat Invocation of MediaRecorder.start(), AudioRecord.startRecording(), or VOICE_CALL audio source
System Settings (DC0118) MobileEDR:telemetry Microphone sensor activation or audio recording session initiated by application process
MobileEDR:telemetry Application transitions to background or executes while screen locked during microphone session
Application Permission (DC0114) android:MDMLog Application granted or retaining RECORD_AUDIO permission or privileged CAPTURE_AUDIO_OUTPUT capability
Process Creation (DC0032) MobileEDR:telemetry Application writes audio buffer or recorded audio file into application storage directories
Mutable Elements
Field Description
RecordingDurationThreshold Minimum microphone session duration before triggering detection to reduce noise from short legitimate captures.
BackgroundCapturePolicy Environment-specific baseline for legitimate background microphone usage
CaptureToNetworkTimeWindow Time window correlating microphone activation with outbound network traffic.

AN1773

A defender observes an application with declared microphone capability initiating microphone resource use through iOS audio frameworks, potentially during background execution or shortly after a silent wake event, followed by sustained audio capture and outbound encrypted traffic suggesting audio streaming or upload activity.

Log Sources
Data Component Name Channel
System Settings (DC0118) MobileEDR:telemetry Microphone sensor activation or audio recording session initiated by application process
MobileEDR:telemetry Application transitions to background or executes while screen locked during microphone session
OS API Execution (DC0021) iOS:unifiedlog Invocation of AVAudioRecorder, AVCaptureSession, or related audio capture framework calls
Process Creation (DC0032) MobileEDR:telemetry Application writes audio buffer or recorded audio file into application storage directories
Application Permission (DC0114) iOS:MDMLog Application installed with NSMicrophoneUsageDescription entitlement indicating microphone capability
Mutable Elements
Field Description
ExpectedAudioAppsBaseline Allow-list of legitimate applications expected to record audio on the device.
BackgroundWakeCorrelationWindow Time window correlating background wake events with microphone activation.
MicSessionDurationThreshold Minimum microphone recording duration considered suspicious.
MicToNetworkCorrelationWindow Time window linking microphone activation to outbound network activity.
UplinkBytesThreshold Threshold for outbound traffic volume indicating possible audio upload.